DESCRIPTION OF OVERALL CENTER (provided by applicant): This application represents the competing renewal of the Boston Obesity/Nutrition Research Center. The Boston Obesity/Nutrition Research Center represents a collaboration of four major institutions representing three major universities in Boston, all located within a 1.5-mile radius of each other. The Boston Obesity Center includes the New England Medical Center, the Beth Israel Deaconess Medical Center, the Harvard School of Public Health, and Boston Medical Center. These institutions represent respectively Tufts University, Harvard University, and Boston University. The Boston Obesity/Nutrition Research Center consists of four Core Laboratories. These include an Adipocyte Core, directed by Dr. James Kirkland, an Epidemiology Core, directed by Dr. Graham Colditz at the Harvard School of Public Health, a Human Metabolic and Genetic Core, directed by Dr. Ernst Schaefer at the New England Medical Center, and a Transgenic Core at the Beth Israel Deaconess Medical Center directed by Dr. Bradford Lowell. The Obesity Center offers multiple opportunities for education and training in obesity research to fellows on training grants held by Obesity Center investigators in each of the collaborating universities. The investigators represented in this application are Principal Investigators on 105 funded NIH grants, approximately 86 of which are directed at the study of obesity, energy metabolism or other nutritional disease. In the past five years, Boston Obesity Center investigators have published over 300 papers with Center support. Currently, fifteen percent of the Obesity Center budget provides support for pilot and feasibility studies. Pilot and feasibility award recipients have published 54 papers and received a total of 25 grants from NIH or other funding agencies based on the data obtained from their Center funded investigation.